Skip to content

Research at St Andrews

Structurally stable Mg-doped P2-Na2/3Mn1-yMgyO2 sodium-ion battery cathodes with high rate performance: insights from electrochemical, NMR and diffraction studies

Research output: Contribution to journalArticle

DOI

Open Access permissions

Open

Author(s)

Raphaële Clément, Juliette Billaud, Robert Armstrong, Gurpreet Singh, Teófilo Rojo, Peter G. Bruce, Clare P. Grey

School/Research organisations

Abstract

Sodium-ion batteries are a more sustainable alternative to the existing lithium-ion technology and could alleviate some of the stress on the global lithium market as a result of the growing electric car and portable electronics industries. Fundamental research focused on understanding the structural and electronic processes occurring on electrochemical cycling is key to devising rechargeable batteries with improved performance. We present an in-depth investigation of the effect of Mg doping on the electrochemical performance and structural stability of Na2/3MnO2 with a P2 layer stacking by comparing three compositions: Na2/3Mn1-yMgyO2 (y = 0.0, 0.05, 0.1). We show that Mg substitution leads to smoother electrochemistry, with fewer distinct electrochemical processes, improved rate performance and better capacity retention. These observations are attributed to the more gradual structural changes upon charge and discharge, as observed with synchrotron, powder X-ray, and neutron diffraction. Mg doping reduces the number of Mn3+ Jahn-Teller centers and delays the high voltage phase transition occurring in P2-Na2/3MnO2. The local structure is investigated using 23Na solid-state nuclear magnetic resonance (ssNMR) spectroscopy. The ssNMR data provide direct evidence for fewer oxygen layer shearing events, leading to a stabilized P2 phase, and an enhanced Na-ion mobility up to 3.8 V vs. Na+/Na upon Mg doping. The 5% Mg-doped phase exhibits one of the best rate performances reported to date for sodium-ion cathodes with a P2 structure, with a reversible capacity of 106 mAhg-1 at the very high discharge rate of 5000 mAg-1. In addition, its structure is highly reversible and stable cycling is obtained between 1.5 and 4.0 V vs. Na+/Na, with a capacity of approximately 140 mAhg-1 retained after 50 cycles at a rate of 1000 mAg-1.
Close

Details

Original languageEnglish
Pages (from-to)3240-3251
Number of pages12
JournalEnergy & Environmental Science
Volume9
Issue number10
Early online date19 Aug 2016
DOIs
StatePublished - 1 Oct 2016

Discover related content
Find related publications, people, projects and more using interactive charts.

View graph of relations

Related by author

  1. Evidence of enhanced ion transport in Li-rich silicate intercalation materials

    Billaud, J., Eames, C., Tapia-Ruiz, N., Roberts, M. R., Naylor, A. J., Armstrong, A. R., Islam, M. S. & Bruce, P. G. 7 Jun 2017 In : Advanced Energy Materials. 7, 11, 9 p., 1601043

    Research output: Contribution to journalArticle

  2. Na2Fe(C2O4)F2: a new iron-based polyoxyanion cathode for Li/Na ion batteries

    Yao, W., Sougrati, M-T., Hoang, K., Hui, J., Lightfoot, P. & Armstrong, A. R. 14 Mar 2017 In : Chemistry of Materials. 29, 5, p. 2167-2172 6 p.

    Research output: Contribution to journalArticle

  3. A novel copper oxalate, Na2Cu(C2O4)2

    Yao, W., Armstrong, A. R. & Lightfoot, P. 5 Dec 2016 In : Zeitschrift für Anorganische und Allgemeine Chemie. 642, 23, p. 1345-1349 5 p.

    Research output: Contribution to journalArticle

  4. High voltage Mg-doped Na0.67Ni0.3-xMgxMn0.7O2 (x = 0.05, 0.1) Na-ion cathodes with enhanced stability and rate capability

    Singh, G., Tapia-Ruiz, N., Lopez Del Amo, J. M., Maitra, U., Somerville, J. W., Armstrong, A. R., Martinez de Ilarduya, J., Rojo, T. & Bruce, P. G. 26 Jul 2016 In : Chemistry of Materials. 28, 14, p. 5087-5094 8 p.

    Research output: Contribution to journalArticle

  5. Li(V0.5Ti0.5)S2 as a 1V lithium intercalation electrode

    Clark, S. J., Wang, D., Armstrong, A. R. & Bruce, P. G. 21 Mar 2016 In : Nature Communications. 7, p. 1-7 7 p., 10898

    Research output: Contribution to journalArticle

Related by journal

  1. Role of coal characteristics in the electrochemical behaviour of hybrid direct carbon fuel cells

    Fuente Cuesta, A., Jiang, C., Arenillas, A. & Irvine, J. T. S. 1 Sep 2016 In : Energy & Environmental Science. 9, 9, p. 2868-2880 13 p.

    Research output: Contribution to journalArticle

  2. Na0.67Mn1-xMgxO2 (0 <= x <= 0.2): a high capacity cathode for sodium-ion batteries

    Billaud, J., Singh, G., Armstrong, A. R., Gonzalo, E., Roddatis, V., Armand, M., Rojob, T. & Bruce, P. G. Apr 2014 In : Energy & Environmental Science. 7, 4, p. 1387-1391 5 p.

    Research output: Contribution to journalArticle

  3. Step-change in high temperature steam electrolysis performance of perovskite oxide cathodes with exsolution of B-site dopants

    Tsekouras, G., Neagu, D. & Irvine, J. T. S. Jan 2013 In : Energy & Environmental Science. 6, 1, p. 256-266 11 p.

    Research output: Contribution to journalArticle

  4. Demonstration of high power, direct conversion of waste-derived carbon in a hybrid direct carbon fuel cell

    Jiang, C., Ma, J., Bonaccorso, A. D. & Irvine, J. T. S. May 2012 In : Energy & Environmental Science. 5, 5, p. 6973-6980 8 p.

    Research output: Contribution to journalArticle

ID: 245238459